5.56mm cartridge; The most used round in NATO Armed Forces. A relatively new round introduced in the 1960's with the M-16, itself the second most produced assault rifle after the Kalashnikov AK 47.

7.62mm cartridge "Full Metal Jacket": An older far more powerful assault rife - Light/medium/general purpose machine gun round. Was largely replaced with the 5.56 during the 1980s/90s, but still the most common round for medium and GP machine guns.

0.5 cal cartridge. The largest small arms round commonly used in NATO Armed Forces. Used in the M2 Browning heavy machine gun and similar weapons.